Lesson 8: Human Toxicity

Understanding Potential Health Risks


  • Human toxicity evaluates the adverse effects of substances on human health.
  • Assessing human toxicity in life cycle assessments (LCAs) helps identify potential health risks related to products or processes.


  • Human toxicity assesses the toxicity and exposure potential of chemicals or pollutants during a product’s life cycle.
  • It considers various health endpoints, such as carcinogenicity, respiratory effects, reproductive toxicity, and systemic toxicity.
  • LCIA evaluates potential risks to human populations through inhalation, ingestion, or dermal contact with hazardous substances.


  • Exhaust Emissions: Vehicle exhaust contains pollutants like carbon monoxide (CO), nitrogen oxides (NOx), volatile organic compounds (VOCs), and fine particulate matter (PM2.5). Prolonged exposure can lead to respiratory problems, cardiovascular diseases, and adverse effects.
  • Fuel Spills and Leaks: Accidental fuel spills can contaminate soil and water with toxic substances like benzene, toluene, and xylene, known to be harmful to humans.
  • Noise Pollution: Vehicle use contributes to noise pollution, leading to stress, sleep disturbances, hearing loss, and other health issues.
  • Indoor Air Pollution: Vehicles idling in enclosed spaces can release harmful gases, such as carbon monoxide (CO), potentially causing health risks.
  • Maintenance Chemicals: Chemicals used in vehicle maintenance, if not handled, stored, or disposed of properly, can expose individuals to health hazards.


  • Cancerous Human Toxicity: Focuses on substances’ potential to cause or increase the risk of cancer development. It assesses carcinogenicity based on scientific evidence.
  • Non-Cancerous Human Toxicity: Examines adverse health effects from substances that do not primarily induce cancer, including respiratory effects, neurotoxicity, reproductive toxicity, developmental toxicity, and systemic toxicity.


  • Human toxicity in LCA assesses the potential health risks associated with products or processes.
  • Vehicles can contribute to human toxicity through exhaust emissions, fuel-related issues, noise pollution, and maintenance chemicals.
  • Understanding these impacts guides efforts to minimize exposure and promote human health and safety.
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